Jean-Louis-Paul-François de Noailles, 2nd duc d'AYEN (1739-1824), military officer and chemist, member of the Académie des sciences, of which he was president 3 times. Autograph letter (written in the 3rd person) to Charles Claude Flahaut de La Billarderie comte d'Angiviller (1730-1809), arts administrator, last director general of the King's buildings. 1 p. in-4. 31 March [1780]. "The Duc d'Ayen sends Monsieur le Comte d'Angiviller the brief he had the honour of telling him about for a water conduit. If this request is contrary to the established rule or to justice, monsieur le comte d'Angiviller is asked to send him a reply [...]".